Test sample positioning system

Abstract

A positioning system for a sample testing machine includes a base pan and a set of independent drive systems for sliding a sample tray across the base pan. Each of the drive systems includes a paddle that engages a side of the sample tray. The paddle is slideably mounted to a shaft with a collar that slides over the shaft. A motor and drive belt is provided to move the collar along the shaft, causing the paddle to engage the side of the sample tray and slide the sample tray across the base pan. Track sections are provided in the base pan to prevent the sample tray from rotating as the paddle slides the sample tray across the base pan.

We claim: 
     
       1. A system for moving a sample holder within a machine, comprising: a base pan having first, second, third and fourth side regions, said sample holder placed on and moved about said machine on said base pan;   a first drive means engageable with said sample holder for moving said sample holder along a first direction along said base pan aligned with said first side region;   a second drive means engageable with said sample holder for moving said sample holder along a second direction along said base pan aligned with said second side region;   a third drive means engageable with said sample holder for moving said sample holder along a third direction along said base pan aligned with said third side region;   a fourth drive means engageable with said sample holder for moving said sample holder along a fourth direction along said base pan aligned with said fourth side region;   said first, second, third and fourth drive means independently operable so as to move said sample holder about said base pan sequentially along said first, second, third and fourth side regions and without requiring the presence of other sample holders on said base pan to effectuate the movement of said sample holder about said first, second, third and fourth side regions of said base pan.   
     
     
       2. The system of claim 1, wherein said first, second, third and fourth side regions of said base pan each comprise an edge portion, said edge portions forming four sides of a rectangle, wherein said second direction and fourth directions are perpendicular to said first and third directions. 
     
     
       3. The system of claim 2, wherein said sample holder comprises a rectangular base and first, second, third and fourth side panels, and wherein said first, second, third and fourth drive means engage said first, second, third and fourth side panels, respectively, to thereby move said sample holder about said base pan. 
     
     
       4. The system of claim 3, wherein said first and third side panels of said sample holder comprise an engaging surface for engaging a complementary engaging surface of said first and third drive means, respectively, enabling said first and third drive means to slide said sample holder over said base pan. 
     
     
       5. The system of claim 1, wherein said base pan further comprises at lease one track section comprising at least one raised ridge for guiding the movement of said sample holder along said base pan. 
     
     
       6. The system of claim 1, wherein said base pan comprises first, second, third and fourth track sections along said first, second, third and fourth side regions, each of said track sections comprising at least one raised ridge for guiding the movement of said sample holder along said base pan. 
     
     
       7. The system of claim 1, wherein said base pan comprises a substantially flat planar surface made from a low-coefficient of sliding friction and low wear material. 
     
     
       8. The system of claim 1, wherein said base pan further comprises at least one drain hole. 
     
     
       9. The system of claim 1, wherein at least one of said first, second, third and fourth drive means is operable in both forward and reverse directions so as to enable movement of said sample holder in forward and reverse direction relative to a respective first, second, third or fourth side region of said base pan. 
     
     
       10. The system of claim 1, wherein each of said first, second, third and fourth drive means comprise (a) a paddle engaging said sample holder moveably mounted to a shaft, the shaft axially fixed with respect to said base ban and extending parallel to said respective first, second third and fourth side regions of said base pan, and (b) means for sliding said paddle relative to said shaft. 
     
     
       11. The system of claim 10, wherein said shaft and paddle are rotatable about an axis relative to said base pan as a unit to allow said paddle to be rotated into and out of engagement with said first, second, third and fourth side panels of said sample holder, respectively.